Ekjättars framtid : en fallstudie av gammelekar idag och i framtiden vid olika skötsel- och restaureringsscenarier i Hjulstaområdet, Enköpings kommun

Abstract: This Master's thesis work was done at SLU, Uppsala, Sweden in cooperation with Upplandsstiftelsen and Uppsala County Council. The studied area is pointed out as an area for EU´s LIFE project, NATURA 2000, concerning the Scarabid beetle Osmoderma eremita. The studied area lies in an agricultural landscape rich on deciduous trees, about 15 km south of Enköping in the County of Uppland. The species is dependent on large, old, hollow trees, which are exposed to sunlight, usually oak trees in this area. I studied the area in detail concerning large old trees (>70cm ø), middle-aged oak trees and young oak trees. I selected 39 smaller areas which I studied separately and estimated their potential to harbour O. eremita and other redlisted old-tree-species, today and in the future. This material has then been treated with a landscape-based view. I found that restoring and managing the whole area, to reach the maximum possible amount of old oak trees, may not be feasible if the cost is weighed against the benefit. Therefore I have recommended a management plan for the area that I find reasonable to follow. Four scenarios concerning the consequences for old oaks and O. eremita were modelled over the next 100 years. These scenarios include: actively restoring the area according to the recommended management plan; not restoring any area, restoring the area completely according to the management plan and a scenario with a higher ambition level than the recommended management plan. The scenarios indicate that it is of a very high value to O. eremita and other red listed species to follow the recommended management plan and to complement this plan in the future with more areas if possible. According to the analysis, by following the management plan there could be 620 oak trees of a dimension great enough to harbour O. eremita in 100 years time instead of 139 if nothing is done. If nothing is done at all a lot of old oak trees will be lost over the next 50 to 100 years.